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Wednesday, July 11, 2018

Asteroid 2016 BS30 = 2010 HD50 - Cometary origin?

Horizon Web data
(2016 BS30)

Classification: Outer Main-belt Asteroid          SPK-ID: 3743356
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

[ show orbit diagram ]

Orbital Elements at Epoch 2458200.5 (2018-Mar-23.0) TDB
Reference: JPL 9 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .3478863638049197 7.7899e-07
a 3.820502999526835 7.8608e-07 au
q 2.491402103115656 3.4304e-06 au
i 11.67728524676726 7.6434e-05 deg
node 326.2245320214484 9.1269e-05 deg
peri 245.4466373090264 0.00026973 deg
M 60.18000341810182 0.00025871 deg
tp 2457744.537683238532
0.0018283 JED
period 2727.590972265617
n .1319845987395147 4.0734e-08 deg/d
Q 5.149603895938015 1.0596e-06 au
Orbit Determination Parameters
   # obs. used (total)      54  
   data-arc span      4641 days (12.71 yr)  
   first obs. used      2003-08-26  
   last obs. used      2016-05-10  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      1  
   fit RMS      .55107  
   data source      ORB  
   producer      Otto Matic  
   solution date      2018-Jul-09 06:23:30  

Additional Information
 Earth MOID = 1.51491 au 
 Jupiter MOID = .65024 au 
 T_jup = 2.935 

Clones generation

I generated 100 clones trying to achieve the same orbital parameter distribution as shown above (mean and sigma).

This is a table comparing what has been achieved versus the target:

clones_mean clones_sd target_mean target_sd
q 2.4914019 0.0000034 2.4914021 0.0000034
e 0.3478864 0.0000008 0.3478864 0.0000008
i 11.6772762 0.0000767 11.6772853 0.0000764
peri 245.4466251 0.0002691 245.4466373 0.0002697
node 326.2245392 0.0000916 326.2245320 0.0000913
tp 2457744.5376278 0.0018291 2457744.5376832 0.0018283

Backward simulation
I used the Bulirsch-Stoer algorithm implemented by the Mercury software by J.E.Chambers (1999):
"A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies."
Monthly Notices of the Royal Astronomical Society, vol 304, pp793-799.

           Integration parameters

   Algorithm: Bulirsch-Stoer (general)

   Integration start epoch:         2458200.5000000 days
   Integration stop  epoch:      -100000000.0000000
   Output interval:                     100.000
   Output precision:                 medium

   Initial timestep:                 .050 days
   Accuracy parameter:              1.0000E-12
   Central mass:                    1.0000E+00 solar masses
   J_2:                              0.0000E+00
   J_4:                              0.0000E+00
   J_6:                              0.0000E+00
   Ejection distance:               1.0000E+02 AU
   Radius of central body:          5.0000E-03 AU

   Includes collisions:                 no
   Includes fragmentation:              no
   Includes relativity:                 no

The arbitrary threshold to consider an asteroid to be ejected from the solar system (or to enter it in case of backward simulation) is 100 au.

All planets from Mercury to Pluto plus asteroids Ceres, Pallas and Vesta have been taken into account.

Simulation results
76 out of 100 initial clones have entered the solar system from a distance greater than 100 au.

The graph below has to be read from right to left (the number of clones decreases as you go in the past - the simulation time has been divided into 10 intervals).

The arrival time into the solar system has the following density distribution:

In the following graphs, the simulation time has been divided into 10 intervals: in every interval and for every clone we find the maximum value for the relevant orbital parameter.

Orbit Specific Energy

Some clones were on a hyperbolic orbit with the following v-infinity:

Orbit eccentricity

Orbit Inclination

Analysis of Close Approaches

Kind Regards,
Alessandro Odasso

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